HEPALOCYTE NUCLEAR FACTOR NETWORK IN BETA CELL FUNCTION

β 细胞功能中的肝细胞核因子网络

• 批准号: 6381451
• 负责人: MARKUS STOFFEL
• 金额: $ 30.42万
• 依托单位: ROCKEFELLER UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1998
• 资助国家: 美国
• 起止时间: 1998-09-30 至 2003-09-29
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6381451
• 关键词: clinical research; diabetes mellitus genetics; gene induction /repression; genetically modified animals; glucose metabolism; hormone regulation /control mechanism; human subject; insulin; laboratory mouse; laboratory rat; noninsulin dependent diabetes mellitus; pancreatic islet function; pancreatic islets; protein structure function; tissue /cell culture; transcription factor

DESCRIPTION (taken from the application) Early-onset type 2 diabetes (MODYs) are monogenic forms of NIDDM characterized by an early disease-onset and by defects in insulin secretion. Mutations in th genes encoding HNF4theta and HNF1theta lead to two clinically indistinguishabl forms of NIDDM (MODY1 and MODY3, respectively). HNF4theta is an upstream regulator of HNF1theta and both genes define a transcriptional hierarchy believed to be essential for normal pancreatic Beta-cell function. We have shown that HNF3beta is a strong transactivator of HNF4theta gene expression an that HNF3theta is a negative regulator of HNF4theta and downstream target gene transcription. This shows that HNF3theta and HNF3beta have antagonistic transcriptional regulatory functions in vivo and suggests that HNF3beta is the master regulator of a balanced transcription factor hierarchy essential for normal pancreatic islet function. We now propose to study the role of the HNF-transcriptional regulatory network in pancreatic islets in normal and diabetic conditions. We propose to generate transgenic and knockout mouse models in which the expression of HNF3theta and HNF3beta is altered. We will study gene expression and pancreatic islet function in these mouse models. Thi will include histological analysis, insulin secretion tests of perifused islet and perfused pancreata as well as gene expression studies of the HNF3/HNF4/HNF cascade and downstream targets by quantification of steady state mRNA and protein levels. In a complimentary approach, we propose to study the expressio of HNFs and downstream targets in islets of a rodent model of NIDDM, the Zucke diabetic fatty (ZDF) male rat, during the progression from the prediabetic to the diabetic state. Since we have previously shown that HNF4theta is a key regulator of expression of glycolytic enzymes and GLUT2 we also propose to tes if there is a correlation between expression of HNFs, their target genes and glucose responsiveness of pancreatic Beta-cell lines. Finally, we propose to use visceral endoderm which was derived from HNF3beta and HNF4theta null ES cells as a model system to identify novel HNF3 and HNF4theta target genes. Any novel targets will be characterized and expression will be studied in the mutant mouse models. We hope that a comprehensive analysis of the HNF-transcriptional hierarchy and its regulation of downstream target gene expression will lead to a better pathomolecular understanding of pancreatic islet function. Novel target genes of this pathway can in future be tested for genetic linkage or genetic variation in other forms of MODY/NIDDM and may be potential targets for therapeutic intervention aimed at preserving or improvin Beta-cell function.

描述（取自应用程序）早发2型糖尿病（Modys） 是NIDDM的单基因形式，其特征是早期疾病发作和 胰岛素分泌缺陷。 编码HNF4Theta和的Th基因中的突变 hnf1theta导致两种临床上没有固定的NIDDM形式（Mody1和Mody1和 Mody3分别）。 HNF4Theta是HNF1Theta的上游调节器， 这两个基因都定义了被认为对的转录层次结构 正常的胰腺β细胞功能。 我们已经证明了HNF3Beta是 HNF4THETA基因表达的强反式激活剂，HNF3Theta是一个 HNF4THETA和下游靶基因转录的负调节剂。 这表明HNF3Theta和HNF3Beta具有拮抗转录 体内的调节功能，并表明HNF3Beta是主人 平衡转录因子层次结构的调节器 胰岛功能。 我们现在建议研究 胰岛中的HNF转录调节网络在正常和 糖尿病状况。 我们建议生成转基因和敲除鼠标 HNF3Theta和Hnf3beta的表达的模型发生了变化。 我们 将研究这些小鼠的基因表达和胰岛功能 型号。 这将包括组织学分析，胰岛素分泌测试 perifused Islet和灌注胰腺以及基因表达研究 HNF3/HNF4/HNF级联和下游目标通过量化 状态mRNA和蛋白质水平。 在免费的方法中，我们建议 研究啮齿动物胰岛中HNF和下游靶标的表达 NIDDM模型，Zucke糖尿病脂肪（ZDF）雄性大鼠 从糖尿病前期到糖尿病状态的进展。 因为我们有 先前证明HNF4Theta是表达的关键调节剂 如果有一个 HNF，其靶基因和葡萄糖的表达之间的相关性 胰腺β细胞系的响应能力。 最后，我们建议使用 内胚层来自HNF3Beta和HNF4Theta null ES 细胞作为模型系统，以识别新型的HNF3和HNF4Theta靶基因。 任何新的目标都将被表征，并将在 突变小鼠模型。 我们希望对 HNF转录层次结构及其对下游靶基因的调节 表达将导致对胰腺的更好分子理解 胰岛功能。 将来可以测试该途径的新型靶基因 用于其他形式的Mody/NIDDM的遗传联系或遗传变异 可能是旨在保存或 Imprivin Beta细胞功能。